This invention relates generally to cathode ray tube (CRT) display apparatus and specifically to CRT display apparatus used as subassemblies for original equipment manufacturers (OEM's).
CRT displays are being increasingly used as computer video outputs, video monitors and vehicular displays, as distinct from their traditional roles in television receivers. A CRT display is much simpler than a television receiver since only baseband signal processing circuitry and some means for "scanning" the CRT screen are required. It is quite common to have a small printed circuit board type chassis which, along with the CRT and associated scanning yoke, is supplied as a non-unitary "subassembly" to OEM producers of computers, monitors, vehicular display apparatus and the like, which the OEM installs in a cabinet or equipment of his own. A common practice is to ship all of the components of the CRT display assembly, that is, the CRT, the yoke, and the chassis in connected-together-and-ready-to-operate fashion in a suitable supporting carton. The OEM merely unpacks the assembly and installs the individual connected parts into his own cabinet, usually in conjunction with other equipment of his manufacture.
For many years CRT's have been installed in cabinets by means of a plurality of mounting ears held in position at the four corners of the CRT faceplate by an anti-implosion band tightly embracing the periphery of the faceplate. As is well known, the very tight band exerts compressive forces in the faceplate to provide implosion protection and thereby eliminate the need for a separate safety glass. The cabinet, or panel in the case of a panel mounted CRT assembly, is provided with a corresponding plurality of bosses to which the mounting ears of the CRT are secured, by means of screws or the like. Generally speaking, the bosses and the cabinets are made of plastic.
It would be highly desirable to ship the CRT and all components mounted together, as well as connected together, for convenience and ease of installation in the cabinet of the manufacturer. However, tolerances on placement of the cabinet bosses, location of the mounting ears on the CRT, general cabinet dimensions and a lack of a support chassis have heretofore made it impractical to ship the CRT and components in an easily handled, assembled condition to OEM's.